Caption: Marcellin Pierre Eugene Berthelot (1827-1907), the French chemist and pioneer of organic synthesis and thermochemistry. Before his work, organic chemistry had been concerned with compounds derived from living nature, and little synthesis had been attempted. From 1854 Berthelot used synthetic methods in a systematic way, and built up large molecules from simple starting components. The former idea of a 'vital force' was banished; organic chemistry became simply the chemistry of carbon compounds. He is also noted for his other work on thermochemistry, physiological chemistry and on explosives.